From old times, animal oil or vegetable oil has been used in many applications such as for foods, cosmetics, as well as for medicines.
Heretofore, use of such animal and vegetable oils has been directed mainly to applications for improvement of physical properties of foods and cosmetics or as solvents, dispersants, etc., due to their unique physical properties, i.e., liquidity with high viscosity at ambient temperature.
Recently, analysis of many lipid components existing in such animal and vegetable oils has progressed, which revealed that among the lipids, ceramide associated substances such as ceramide and cerebroside (ceramide glycolipids) have a high moisture retention effect. Also, it has come to be known that the ceramide associated substances exist abundantly in the horny layer of human skin and serve to prevent evaporation of moisture from the body.
Further, it has been clarified that the ceramide associated substances have an effect of preventing the penetration of antigens into the body from the outside and function to be effective against atopic dermatitis. Accordingly, development of ceramide associated substances as medical preparations has recently been under way.
Hitherto, the ceramide associated substances have been extracted from brains and spinal marrow of bovine and ever been supplied. However, in view of the possibility that it could cause bovine hydrophobia to infect to humans and from the viewpoint of prevention of cruelty to animals, their supply has been decreased remarkably so that it is demanded to secure raw materials which substitute for them.
Since chemical structure of the ceramide associated substances is already known, their synthetic products have been produced and come to be used as substitutes for the above natural ceramide associated substances.
However, regarding the synthetic products, safety of reactants used for chemical reactions and of impurities such as by-products produced during the reactions has not been established yet.
Therefore, they must be purified to extremely high degrees of purity, which increases their price. Also, it is pointed out that synthetic products are inferior in effect to natural ceramides.
Under the circumstances, there are strongly demanded for ceramide derivatives of a plant origin which are highly safe and moreover give a good image as a material.
As the ceramide derivatives, those derived from rice (Agric. Biol. Chem., 49, 2753 (1985)) and wheat (Agric. Biol. Chem., 49, 3609 (1985)) are well-known and these cereals originated ceramide derivatives have already been under way of development as materials for cosmetics.
However, although such cereals contain ceramide derivatives, their concentration is very low so that their extraction and purification take much time and cost.
An object of the present invention is to overcome the above-described defects of the prior art and provide a method for efficiently, simply and easily obtaining barley malt oil which contains abundant ceramide derivatives of a plant origin that are highly safe and give a good image as a material.
An additional object of the present invention is to provide barley malt oil which is obtained by such methods as above and contains abundantly highly safe ceramide derivatives.
To achieve the above-described objects, the present inventors have made intensive research, during which were focused on spent grains which is a by-product produced quantitatively according as the production of beer proceeds.
More specifically, in the charging step which is conducted first in the production of beer, wort is obtained by filtration of mash after saccharification, during which procedure spent grains is separated and discharged in large amounts as a by-product.
The spent grains, which is generated quantitatively according as beer is produced, is currently utilized mainly as a cattle feed.
However, in accordance with a recent decline of stockbreeding and an increase in importation of feed and stockbreeding products as a result of deregulation, the demand as a feed is in a decreasing tendency. Accordingly, it has become a problem to find new application of spent grains, in place of usage as a cattle feed.
In the process of studying such a method of efficiently utilizing spent grains, the present inventors have found that spent grains can be used very advantageously as a raw material for producing ceramide derivatives.
That is, the present inventors have found that spent grains contains a large amount of lipid (about 10% in a dry matter), in which there is a very large amount of ceramide derivatives which can be used as a material for cosmetics or a material for medicines so that spent grains can be used very advantageously as a raw material for producing ceramide derivatives.
First, spent grains, from which is recovered most of the lipid contained in the raw material for producing beer such as malt, contains a very large amount of lipid as much as about 10% based on the weight of dry matter.
The lipid components in the spent grains include a lot of ceramide derivatives.
Spent grains, a by-product obtained quantitatively according as beer production process, was already heated at the process of wort production so that thermally unstable lipids therein have been decomposed. Also, by the action of lipase which was generated when barley grains germinated, fatty acid esters were hydrolyzed to free fatty acids.
Hitherto, when ceramide derivatives are extracted from cereals such as rice and wheat, it has been necessary to conduct a step of alkali treatment to separate ceramide derivatives from unnecessary materials such as other phospholipid or neutral lipids.
However, use of spent grains instead of rice or wheat as a raw material for ceramide derivatives enables one to eliminate such a step of separation from unnecessary materials so that a lipid fraction which contains ceramide derivatives abundantly can be obtained in a very simple and easy manner.
In addition, spent grains are safe since it is a by-product in food production derived from plants, and can always be supplied with stable quality.
Therefore, spent grains can be used very advantageously as a raw material for producing ceramide derivatives.
The present invention is made based on the above-described findings and is to provide a method for producing ceramide derivatives contained in spent grains in a simple and easy manner.